This invention relates to a library virtualisation module, and to a library system including a library virtualisation module.
A tape library, such as the ADIC Scalar 100 library, consists of a housing in which is included a robot and a number of ‘elements’, namely a number of tape drivers, plural normal tape slots and at least one import/export tape slot. Tape slots are typically tape receptacles in the walls of the housing, and import/export slots are typically receptacles in a door of the housing, which allow tapes to be introduced into and taken from the library by a human user. Each tape drive typically has a small computer serial interface (SCSI) connection to a single host computer, which also sends SCSI signals to control the robot to move tapes between the tape slots and the tape drives. Tape libraries, or more particularly the robot thereof, are able typically, in response to a request from the host, to determine what tapes it contains in which slots, and to convey this information to the host along with information concerning the number of tape drives, normal slots and import/export slots that it has.
Conventionally, only one host has been able to use a library. However, Spectrologics and Quantum ATC both vend libraries which are able to be connected to plural hosts, enabling each host to use the resources of the library. Digital Interfaces Limited vend a system allowing plural hosts to connect to a robot of a single library via respective TA40 devices. The outputs of the TA40 devices are connected together and to an input/output of the library. Each of these arrangement is satisfactory.